Transcript 14_Pharmacotherapy of Labour

Labor Review
Petrenko N., MD,PhD
1
Critical Factors in Labor
• 5 critical factors
– Birth passage
– Fetus
– Relationship of Maternal Pelvis and
Presenting Part
– Physiologic forces of labor
– Psychosocial considerations
2
3
1 Birth Passage
• Four different types of pelvises, but
frequently mixed types
gynaecoid
anthrapoid
android
platypelloid
4
2 Fetus
• Sutures:
– Frontal
– Sagittal
– Coronal
– Lambdoidal
Lambdoidal
suture
Sagittal
suture
Coronal
suture
Frontal suture
Note: sutures are actually membranous spaces that meet at fontanels
5
Fetus
• ☺Fontanelles: intersection of sutures, allows for
molding, helps identify position
of head
– Anterior (bregma)
• Diamond shaped
• Approx 2-3 cm
• Ossifies in ~12-18 months
– Posterior
• Triangle shaped
• Smaller
• Closes in 8-12 weeks
6
Fetus
• Other landmarks on the fetal head
– Mentum
– Sinciput
– Vertex
– occiput
7
Fetus
• Fetal attitude
– Relation of fetal parts to one another
– Normal: mod flexion of head, flexion of arms
onto chest, flexion of legs onto abdomen
• Changes in attitude can contribute to
longer, more difficult labor or Cesarean
Section
8
Fetus
• Fetal lie
– Relationship of the spine
(cephalocaudal axis) of the fetus to the
spine of the mom
– Longitudinal: parallel
– Transverse: right angle
– Oblique: acute abgle
9
Fetus Fetal lie
Longitudinal
Transverse
10
Fetus
• Fetal presentation
– Body part entering the pelvis (presenting
part)
• Cephalic
• Breech
• Shoulder
11
Fetus Fetal lie
Cephalic
Breech
Shoulder
12
Fetus
• Fetal presentation: Cephalic
– ☺Vertex presentation
• Most common
• Head completely flexed on chest
• Suboccipitobregmatic (Smallest
diameter)
• Occiput in presenting part
13
Fetus
• Fetal presentation: Cephalic
– Military presentation
• Fetal head neither flexed nor extended
• Occipitofrontal diameter presents
• Top of the head is presenting part
14
Fetus
• Fetal presentation:
Cephalic
– Brow presentation
• Fetal head partially
extended
• Occipitomental diameter
presents
• Sinciput is presenting part
15
Fetus
• Fetal presentation: Cephalic
– Face presentation
• Head hyperextended
• Submentobregmatic diameter
presents
• Face is presenting part
16
Fetal presentations
17
18
Fetus
• Fetal presentation:
Breech
– Sacrum is the
landmark
– Complete breech
• Knees and hips are
flexed, thighs on
abdomen (“fetal
position”)
• Buttocks and feet are
presenting parts
19
Fetus
• Fetal presentation:
Breech
– Sacrum is the
landmark
– Frank breech
• Hips flexed, knees
extended
• Buttocks is presenting
part
20
Fetus
• Fetal presentation:
Breech
– Sacrum is the
landmark
– Footling breech
• Hips and legs
extended
• Feet are presenting
parts (single vs
double)
21
Fetus
• Fetal
presentation:
Shoulder
– Acromion
process of
shoulder is
presenting part
22
Station
􀂉In
Station of the head in
relation to ischial spines
Gynaecoid & Android
pelvis distance between
ischial spine to brim is ~5 cm.
􀂉In Anthropoid pelvis
distance is ~7 cm
􀂉In Platypelloid pelvis
distance is ~3 cm
23
Relationship of maternal pelvis and
presenting part
24
Relationship of maternal pelvis and
presenting part
• OA most common, easiest to deliver
• Other positions are considered
malpositions
• Position influences labor and birth
• Largest diameter in posterior position: back
pain, longer 2nd stage
• Can tell position by palpation of abdomen
and Vaginal Examination
25
2 Fetus
• Sutures:
– Frontal
– Sagittal
– Coronal
– Lambdoidal
Lambdoidal
suture
Sagittal
suture
Coronal
suture
Frontal suture
Note: sutures are actually membranous spaces that meet at fontanels
26
Fetus
• ☺Fontanelles: intersection of sutures, allows for
molding, helps identify position
of head
– Anterior (bregma)
• Diamond shaped
• Approx 2-3 cm
• Ossifies in ~12-18 months
– Posterior
• Triangle shaped
• Smaller
• Closes in 8-12 weeks
27
Fetus
• Other landmarks on the fetal head
– Mentum
– Sinciput
– Vertex
– occiput
28
Fetus
• Fetal attitude
– Relation of fetal parts to one another
– Normal: mod flexion of head, flexion of arms
onto chest, flexion of legs onto abdomen
• Changes in attitude can contribute to
longer, more difficult labor or Cesarean
Section
29
Fetus
• Fetal lie
– Relationship of the spine
(cephalocaudal axis) of the fetus to the
spine of the mom
– Longitudinal: parallel
– Transverse: right angle
– Oblique: acute abgle
30
Fetus Fetal lie
Longitudinal
Transverse
31
Fetus
• Fetal presentation
– Body part entering the pelvis (presenting
part)
• Cephalic
• Breech
• Shoulder
32
Fetus Fetal lie
Cephalic
Breech
Shoulder
33
Fetus
• Fetal presentation: Cephalic
– ☺Vertex presentation
• Most common
• Head completely flexed on chest
• Suboccipitobregmatic (Smallest
diameter)
• Occiput in presenting part
34
Fetus
• Fetal presentation: Cephalic
– Military presentation
• Fetal head neither flexed nor extended
• Occipitofrontal diameter presents
• Top of the head is presenting part
35
Fetus
• Fetal presentation:
Cephalic
– Brow presentation
• Fetal head partially
extended
• Occipitomental diameter
presents
• Sinciput is presenting part
36
Fetus
• Fetal presentation: Cephalic
– Face presentation
• Head hyperextended
• Submentobregmatic diameter
presents
• Face is presenting part
37
Fetal presentations
38
39
Fetus
• Fetal presentation:
Breech
– Sacrum is the
landmark
– Complete breech
• Knees and hips are
flexed, thighs on
abdomen (“fetal
position”)
• Buttocks and feet are
presenting parts
40
Fetus
• Fetal presentation:
Breech
– Sacrum is the
landmark
– Frank breech
• Hips flexed, knees
extended
• Buttocks is presenting
part
41
Fetus
• Fetal presentation:
Breech
– Sacrum is the
landmark
– Footling breech
• Hips and legs
extended
• Feet are presenting
parts (single vs
double)
42
Fetus
• Fetal
presentation:
Shoulder
– Acromion
process of
shoulder is
presenting part
43
Station
􀂉In
Station of the head in
relation to ischial spines
Gynaecoid & Android
pelvis distance between
ischial spine to brim is ~5 cm.
􀂉In Anthropoid pelvis
distance is ~7 cm
􀂉In Platypelloid pelvis
distance is ~3 cm
44
Relationship of maternal pelvis and
presenting part
45
Relationship of maternal pelvis and
presenting part
• OA most common, easiest to deliver
• Other positions are considered
malpositions
• Position influences labor and birth
• Largest diameter in posterior position: back
pain, longer 2nd stage
• Can tell position by palpation of abdomen
and Vaginal Examination
46
Physiologic forces of labor
• Primary: uterine muscles (causes dilation
and effacement)
• Secondary: abdominal muscles (for 2nd
stage)
47
Physiologic forces of labor
• Phases of contractions
– Increment
– Acme
– Decrement
• Relaxation
– Uterine muscle rest
– Rest for mom
– Restores oxygenation to baby
48
Physiologic forces of labor
Frequency
Duration
Intensity
49
Physiologic forces of labor
Intensity:
indirect (subjective): palpation: mild,
moderate, strong,
direct (objective): mmHg pressure with
IUPC (intauterine)
50
Physiologic forces of labor
Early labor: mild, short duration,
irregular
As labor progresses: stronger, longer,
more regular, closer together
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Physiologic forces of labor
Bearing down (Pushing)
must be 10cm dilated (complete)
involuntary and voluntary muscles
52
Stages of Labor
☺
• Stage 1
– Onset of regular contractions to complete
dilatation
• Stage 2
– Complete dilatation to birth
• Stage 3
– Birth of infant to birth of placenta
• Stage 4
– Birth of placenta to 1-4 hrs recovery
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Stages of Labor
☺
• Stage 1 divided into 3 phases
– 1 Latent phase: 0-3 cm
• Primip 8.6 hrs
• Multip 5.3 hrs
• May have irregular contractions, short, mild –
moderate
• Excited, talkative, smiling
– 2 Active phase: 4-7 cm
• Primip 4.6 hrs; dilation at least 1.2 cm/hr
• Multip 2.4 ; dilation at least 1.5 cm/hr
• Uterus contraction through 2-5 min, by 40-60 sec,
mod – strong
• ↑ anxiety, sense of hopelessness, fear of loss of
control
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Stages of Labor
☺
• Stage 1 divided into 3 phases cont…
• 3 Transition phase: 8-10 cm
• Primip 3.6 hrs
• Multip variable
• Uterus contraction through 1 ½ - 2 min; 60-90 sec,
mod – strong
• Acutely aware of intensity of uterus contraction,
significant anxiety, restless, can’t get comfortable,
fears being alone, yet may not want anyone to touch
her, hot-cold, apprehensive
– As dilation progresses, ↑ bloody show, ROM.
As gets to closer to complete, ↑ rectal
pressure, splitting feeling, urge to push
55
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Stages of Labor
☺
• 2nd stage
– Usually <2 hrs (less in multips)
– Affected by epidural, maternal pushing,
position of presenting part, size of pelvis
– As head approaches perineum, labia
separate, may see presenting part with
pushing, then recede. Rectum bulges
and flattens
– Crowning
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Stage
s of
Labor
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Stages of Labor
☺
• 3rd stage
– Usually will induced 5 mins. May be up
to 30 mins. Retained after 30 mins.
– Signs of separation
•
•
•
•
Globular shaped uterus
Rise in fundus
Sudden gush or heavy trickle of blood
Lengthening of cord from vagina
– Shiny schultze
– Dirty duncan
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Stages of Labor
☺
• 4th stage
– Blood loss normal up to 500mL (vag del)
– Hemodynamic changes  ↓ BP, ↑ pulse
pressure, tachycardia
– Uterus contracted and midline ~1/2 way
between symphysis and umbilicus.
Within 1st hour about level with umbilicus
– Shaking, hunger, thirst
– Bladder is hypotonic
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Post-term Pregnancy
• > 42 completed weeks
• Cause of true post-term is unknown; often
incorrect dates
• Maternal Risks:
– Large baby and associations
– Psychologic ills
• Fetal-Neonatal Risks:
–
–
–
–
Placental changes  insufficiencies
Oligohydramnios
macrosomia birth trauma, glucose maintenance problems
Meconmium stained fluid (aspiration)
• As pregnancy approached term, fetal well-being studies
done
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Fetal Malposition
• OP position:
– Fetus must rotate 135° or occasionally born in
OP position
– If born OP, increased risk of 3rd or 4th degree
laceration, broken symphysis
– May use forceps or manual rotation
– Positioning: knee chest, pelvic rocking
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Fetal Malpresentation
• Brow
– Usually C/S recommended
– Perinatal morbidity and mortality:
• Trauma: cerebral and neck compression; damage to trachea
and larynx
– Tx: pelvimetry, oxytocin?, C/S
• Face
– Perinatal morbidity and mortality:
• Risk of prolonged labor, fetal edema, swelling of neck and
internal structures, petechiae, ecchymosis
– Tx: C/S in no progress
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Fetal Malpresentation
• Breech
– Most common malpresentation
– Frank breech most common
– Risk of cord prolapse; fetal anomolies 3x
higher
– If vag del: head trauma, fetal entrapment
– Tx: external version (50-60% success), if vag
del: epidural, double set-up
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Fetal Malpresentation
• Shoulder
– Version may be attempted
– C/S
• Compound presentation
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Macrosomia
• >4500 g
• Obese 3-4x more likely to have
macrosomic baby
• ↑risk of perineal lacerations, infection
• Most significant problem is shoulder dystocia
– OB emergency permanent injury of brachial plexus,
fx clavicle, asphyxia, neurologic damage
– Tx:
•
•
•
•
Assessment of adequacy of pelvis
Suprapubic pressure
Intentional breaking of clavicle
?C/S
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Prolapsed Cord
• Umbilical cord precedes presenting part
• May be visible or occult
• More common with
– Abnormal lie
– Low birth weight
– > previous births
– Amniotomy
– Long cord
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68
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Prolapsed Cord
• Key interventions
– Relieve pressure on cord
• Trendelberg or knee chest position
• Oxygen to increase maternal oxygen saturation
• Pressure on the presenting part
– Call for help, but do not leave mother
– Expedite delivery
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Prolapsed Cord
• Maternal Risk
– No direct risk
• Fetal-Neonatal Risk
– Cord compression  ↓O2  possible death or
neurologic compromise
• Tx
– Prevention!
– If palpated, keep pressure off cord
– ☺When ROM occurs, listen to FHTs for full minute; if
decel heard, do vag exam to r/o cord prolapse
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Intrauterine Fetal Demise (IUFD)
• May be found prior to coming to hosp or at
time of admission
• May be unexplained or r/t materanal
disease process or fetal insult
• May be induced right away or wait for
spontaneous labor. C/S not automatically
done
• Pain med give freely
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Intrauterine Fetal Demise (IUFD)
•
•
•
•
•
•
•
•
Provide privacy for families
Listen
Avoid inappropriate consolations
Give accurate info
Obtain mementos
Allow opportunity to see and hold
Provide information re: burial options
Provide support information
74
Premature Rupture of
Membrane
(PROM)
• Spontaneous break in the amniotic sac before onset of
regular contractions
• Mother at risk for chorioamnionitis, especially if the time
between Rupture of Membranes (ROM) and birth is
longer than 24 hours
• Risk of fetal infection, sepsis and perinatal mortality
increase with prolonged ROM.
• Vaginal examinations or other invasive procedure
increase risk of infection for mother and fetus.
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PROM
Signs of Infection
• Maternal fever
• Fetal tachycardia
• Foul-smelling vaginal discharge
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PROM
Detecting Amniotic Fluid
• Nitrazine
• Ferning: Place a smear of fluid on a slide
and allow to dry. Check results. If fluid
takes on a fernlike pattern, it is amniotic
fluid.
• Speculum exam
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fernlike pattern
78
PROM
Treatment
• Depends on fetal age and risk of infection
• In a near-term pregnancy, induction within
12-24 hours of membrane rupture
• In a preterm pregnancy (28 -34 weeks),
the woman is hospitalized and observed
for signs of infection. If an infection is
detected, labor is induced and an antibiotic
is administered
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PROM
Nursing Interventions
• Explain all diagnostic tests
• Assist with examination and specimen
collection
• Administer IV Fluids
• Observe for initiation of labor
• Offer emotional support
• Teach the patient with a history of PROM
how to recognize it and to report it
immediately
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Signs of Preterm Labor
• Rhythmic uterine contraction producing
cervical changes before fetal maturity
• Onset of labor 20 – 37 weeks gestation.
• Increases risk of neonatal morbidity or
mortality from excessive maturational
deficiencies.
• There is no known prevention except for
treatment of conditions that might lead to
preterm labor.
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Treatment of Preterm Labor
• Used if tests show premature fetal lung
development, cervical dilation is less than
4 cm, & there are no that contraindications
to continuation of pregnancy.
• Bed rest, drug therapy (if indicated) with a
tocolytic
82
Preterm Labor
Pharmacotherapies
• Terbutaline (Brethine), a beta-adrenergic
blocker, is the most commonly used
tocolytic
• Side effects: maternal & fetal tachycardia,
maternal pulmonary edema, tremors,
hyperglycemia or chest pain, and
hypoglycemia in the infant after birth
• Ritodrine (Yutopar) is less commonly used.
83
Preterm Labor
Pharmacotherapies
 Magnesium Sulfate
 Acts as a smooth muscle relaxant and leads
to decreased blood pressure
 Many side effects including flushing, nausea,
vomiting and respiratory depression
 Should not be used in women with cardiac or
renal impairment
 Excreted by the kidneys
84
Perterm Labor
Pharmacotherapies
• Corticosteroids
 Help mature fetal lungs
 Betamethasone or dexamethasone
 Most effective if 24 hours has elapsed before
delivery
85
Nursing Interventions with
Preterm Labor
Nursing Intervention in Premature labor
 Observe for signs of fetal or maternal distress
 Administer medications as ordered
 Monitor the status of contractions, and notify
the physician if they occur more than 4 times
per hour.
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Nursing Interventions with
Preterm Labor
Nursing Intervention in Premature labor
 Encourage patient to lie on her side
 Bed rest encouraged but not proven effective
 Provide guidance about hospital stay,
potential for delivery of premature infant and
possible need for neonatal intensive care
87
Nursing Interventions with
Preterm Labor
Discharge teaching for home care:
 Avoid sex in any form
 Take medications on time
 Teach to recognize the signs of preterm labor
and what to do
88
Birth Related Procedures
89
Procedures
• Version
– External
– Internal
• Cervical Ripening
– Cervidil
– Cytotec
• Amnioinfusion
– ~250-500 mL warmed saline or LR is infused into
uterus via IUPC over 20-30 min
– Used to correct variables, dilute mec stained fluid
90
Labor Induction
• Stimulation of U/C before spontaneous
onset of labor
• Prior to starting induction
– Verification of gestation age
– Confirmation of fetal presentation
– Assessment of risk factors
– Well-being assessment of mom and baby
– Cervical Assessment
91
Labor Induction
• Cervical Assessment (Bishop’s Score)
– Higher the score, more successful the
induction will be
– Favorable cervix is most important criteria for
successful induction
92
Bishop’s Score)
Cervical
dilatation
1-2
3-4
5-6
Cervical
effacement
0-40
40-80
80+
posterior
medial
Anterior
Consistency of
cervix
Firm
Medium
soft
Station of
presenting
part
-2
-1/0
+1/+2
Position of
cervix
93
Labor Induction
• Methods
– Stripping membranes
– Oxytocin
• ☺Always given via IV pump (may be given IM after
del)
• Site closest to insertion
• Continuous EFM
• Risks
–
–
–
–
Hyperstimulation
Uterine rupture
Water intoxication
Fetal risks associated with maternal problems,
hyperbilirubinemia, trauma from rapid birth
94
Episiotomy
• Decline over the years
• May make it more likely will have deep
tears
• Lacerations heal more quickly in absence
of epis
• 3rd or 4th degree lacerations more likely
with epis
95
Episiotomy
• Midline
– from vag orifice to fibers of rectal sphincter
– Less blood loss, easier to repair, heals with less
discomfort
• Mediolateral
– From midline of posterier forchette to 45° angle to
right or left
– Provides more room but has > blood loss, longer
healing time and more discomfort
• Tx
– Pain relief measures
– Ice
– Inspect!
96
97
98
Operative Assisted Deliveries
• Forceps
– Maternal complications
• Trauma
• Increased pain in pp period
• Weakening of the pelvic floor
– Fetal-neonatal complications
•
•
•
•
Caput
Caphalohematoma
Transient facial paralysis
trauma
99
Operative Assisted Deliveries
• Vacuum Extractor
– Longer duration of suction, more likely
scalp injury
– Maternal complications
• Perineal trauma
• Edema
• Genital tract and anal sphincter probs (< than with forceps)
– Neonatal complications
•
•
•
•
•
•
•
Scalp lacerations
Bruising/subdural hematoma
Cephalohematoma
Jaundice
Fx clavicle
Retinal hemorrhage
death
100
Cesarean Birth
•
•
•
•
•
1970 - ~5%
1988 – 24.7%
2001 – 21%
2005 - ? But higher
Indications
–
–
–
–
–
Failure to progress/descend
Previa/abruption/prolapse cord
Non-reassuring fetal status
Malpresentation
Previous C/S
• Maternal morbidity and mortality is > than vag
delivery
101
Cesarean Birth
• Technique
– NOTE: Skin incision NOT
indicative of uterine incision
– Transverse (Pfannenstiel)-lower uterine
segment
• Adv: below pubic hair line, less bleeding, better
healing
• Disadv: difficult to extend if needed, requires more
time, if adipose fold difficult to keep clean and dry
– Vertical-between naval and symphysis
• Adv: quicker, more room
• Disadv: scar obvious, longer
102
Cesarean Birth
103
Cesarean Birth
104
Cesarean Birth
• Technique
– Uterine incision (type depends on
need for C/S)
– Transverse-lower uterine segment
• Adv: thinnest  less blood loss, only mod
dissection of bladder, easier to repair, site less
likely to rupture during subsequent pregnancies,
less chance of adherence of bowel or omentum to
incision line
• Disadv: takes longer, limited in size due to major
blood vessels, greater tendency to extend into
uterine vessels
105
Cesarean Birth
• Technique
– Lower Uterine Segment Vertical Incision
• Preferred for multiple gestation,
abnormal presentation, previa,
preterm, macrosomia
• Adv: more room
• Disadv: may extend into cx, more extensive
dissection of the bladder is necessary, if
extends upward hemostasis and closure
more difficult, higher risk of rupture in
subsequent pregnancies
106
Cesarean Birth
• Technique
– Classic incision
• Upper uterine segment
• Adv: more room, quicker to do
• Disadv: more blood loss, difficult to repair,
higher risk of rupture in subsequent
pregnancies
107
Cesarean Birth
• Prep for C/S (time dependent)
– Permits
– IV
– Foley
– Shave
NPO
Oral/IV antacids, H2 inhibitors
Teaching
• Immediate PP care
– Freq vs (q 5-10 min)
– Check dressing
– Lochia and uterus
Lungs
I&O
Anesthetic level
108
VBAC (vaginal birth after cesarean)
•
•
•
•
That was then, this is now
Specific criteria
Must sign consent
Contraindications
– Classic incision or previous fundal uterine
surgery
• Most common risk is hemorrhage and
uterine rupture
109
Placental accreta
• occurs when the placenta attaches too deep in
the uterine wall but it does not penetrate the
uterine muscle. Placenta accreta is the most
common accounting for approximately 75% of all
cases.
• Approximately 1 in 2,500 pregnancies
experience placenta accreta, increta or percreta.
• There are two further variants of the condition
that are known by specific names and are
defined by the depth of their attachment to
uterine wall.
110